[EMAIL PROTECTED] (Kevin Oberman) writes: >> From: Martin Burnicki <[EMAIL PROTECTED]> >> Date: Wed, 24 Sep 2008 09:24:43 +0200 >> Sender: [EMAIL PROTECTED] >> >> >> Kevin, >> >> Kevin Oberman wrote: >> [...] >> > Another thought...could it be PPS that is causing it? After all, the pin >> > on the bulkhead connector is still getting the PPS signal. I am using the >> > kernel PPS implementation, so could that be training the kernel even >> > though ntp is not using it? >> >> That's also what I've got in mind when I read you latest posts. >> >> Can you disconnect the PPS signal and see what's happening?
>Martin, >We have a winner! It is the PPS. If I take that out, it syncs correctly >to all of the other systems. >Looks like PPS will train whatever sync source is selected, not just the >reference clock. So it was reference clock drifting off time with no >input signal, marking the time as inaccurate so that ntpd was ignoring >it, but still sending out the PPS such which the system was still >listing to via the kernel NTP_SYNC, but was training the clock without >paying any attention to the validity or presence of time from the >reference clock. I at least am confused. What is generating the pps signal. I would have thought it was the hardware clock that you say is misbehaving. If so it should not send out a PPS signal at all. Or is it your computer itself that is sending out a PPS based on its own clock? In that case you certainly should NOT be using it as a source of time. >It looks like ntpd should be disabling PPS_SYNC when the reference clock >is bad, but is not doing so. Note: I am referring ONLY to the kernel If the reference clock is bad it should not be sending out a PPS. Why is it doing so? >using PPS_SYNC. ntpd, itself seems to not pay attention to PPS unless >the reference clock is selected for sync. >If I get some time, I'm going to look at the PPS code in ntpd and see it >this can be done easily. If that pps is really not a good pps source coming from an idependent harware time source, it should not be enabled at all. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
